The invention relates to a bicycle frame made by injection molding pellets of a long glass fibre reinforced polypropylene composition having a core containing glass fibres and an impregnating agent and a sheath of polypropylene surrounding said core, wherein the pellets have an average length of at least 1 mm, the amount of the glass fibers is 10 to 70 wt % with respect to the composition and the polypropylene has a flexural modulus determined according to ASTM D790A of at least 1000 N/mm.sup.2.

A crank arm for a bicycle may include a body extending along a body axis and having a first body end and a second body end axially spaced apart from the first body end. The insert may also include an insert provided toward the first body end. The insert may include a base portion having a radially outer surface. At least one extension may extend outwardly from the radially outer surface and may be encased within a corresponding recess in the body whereby relative planar movement between the body and the at least one extension in a first plane. The retaining portion may have a retaining portion width measured in the first direction and the retaining width may be greater than the throat width thereby inhibiting relative radial movement between the at least one extension and the recess and preventing radial extraction of the extension from the corresponding recess.

A crank arm for a bicycle may include a body extending along a body axis and having a first body end and a second body end axially spaced apart from the first body end. The insert may also include an insert provided toward the first body end. The insert may include a base portion having a radially outer surface. At least one extension may extend outwardly from the radially outer surface and may be encased within a corresponding recess in the body whereby relative planar movement between the body and the at least one extension in a first plane. The retaining portion may have a retaining portion width measured in the first direction and the retaining width may be greater than the throat width thereby inhibiting relative radial movement between the at least one extension and the recess and preventing radial extraction of the extension from the corresponding recess.

A vehicle includes a frame including a lower frame portion made from a first material and an upper frame portion made from a second material different from the first material, a center of gravity of the upper frame portion being above a center of gravity of the lower frame portion, at least one front suspension system connected to the lower frame portion, at least one front ground engaging member connected to the front suspension systems, at least one rear suspension system connected to the lower frame portion, at least one rear ground engaging member operatively connected to the rear suspension system, a power pack connected to and supported by the lower frame portion, a seat connected to and supported by at least one of the upper frame portion and the lower frame portion, and at least one body panel connected to and supported by the upper frame portion.

The invention relates to a method of manufacturing a plastic frame for a two-wheeler having at least one hollow space in the interior by means of plastic injection molding having a series of method steps, wherein a fluid is injected to displace the plastic core from the component cavity after the injection of a preferably thermoplastic plastic melt into a closed injection molding tool.

The invention relates to a method of manufacturing a plastic frame for a two-wheeler having at least one hollow space in the interior by means of plastic injection molding having a series of method steps, wherein a fluid is injected to displace the plastic core from the component cavity after the injection of a preferably thermoplastic plastic melt into a closed injection molding tool.

A joint structure of a composite bicycle frame includes a base layer and at least one reinforcing layer. The base layer is made of a first polymeric matrix material doped with a plurality of first fibers. The first fibers have random fiber orientation, and the base layer has a first thickness. The reinforcing layer is adhesively connected to the base layer. The reinforcing layer is made of a second polymeric matrix material doped with a plurality of second fibers. The second fibers have a single fiber orientation. The reinforcing layer has a second thickness which is smaller than the first thickness of the base layer.

A joint structure of a composite bicycle frame includes a base layer and at least one reinforcing layer. The base layer is made of a first polymeric matrix material doped with a plurality of first fibers. The first fibers have random fiber orientation, and the base layer has a first thickness. The reinforcing layer is adhesively connected to the base layer. The reinforcing layer is made of a second polymeric matrix material doped with a plurality of second fibers. The second fibers have a single fiber orientation. The reinforcing layer has a second thickness which is smaller than the first thickness of the base layer.

The swing arm for the saddle riding vehicle that supports a wheel in a swingable manner includes a swing arm main body made of a fiber reinforced resin. The swing arm main body is formed to be hollow, and an embedded member of a material different from the fiber reinforced resin is embedded in such a manner as to make solid at least part of the hollow portion of the swing arm main body.

A structural element of a cycle includes at least one tubular sheath provided with an outer wall delimiting, with an inner partition, at least one cavity in which a vibration damping system is accommodated. The sheath includes at least two internal cavities, each delimited between the inner partition and the outer wall, one of the internal cavities forming a housing in which the damping system is accommodated and attached.